I have got confused over my un 71 bb. It was poking out the drive side a so I decided to tighten the cup that side. The drive side tightened clockwise?. I undid the non drive side and a un71 dropped out. This must mean both the cups are loose. A bit wierd

On all the bikes I've had the DRIVE SIDE has tightened up ANTI-CLOCKWISE (ie lefty-tighty).

The NON-DRIVE-SIDE has tightened up CLOCKWISE (ie righty-tighty, aka the "normal" way).

you said you unscrewed the non-drive side and the bottom bracket popped out? Usually with the Shimano sealed bottom brackets the main body is screwed into the BB shell from the drive side, and the plastic or metal "sleeve" is screwed in from the non-drie side.

Should be a lefty , as everyone suggested , my '98 Kilauea was . Easy way to remember if you have a senior moment , the cups undo the way the cranks go around . Don't know what happens if you put bracket in wrong way around though , never tried it I'm afraid .Mike

There were some early Shimano cartridge BBs with the loose cup on the right, but I'd cannot remember if they were UN70 or 71.

If somebody didn't know this then the BB might have been screwed from the wrong side, cutting itself a thread across the bottom bracket as it went. Best to look at the frame bottom bracket threads to see if it's happened. Alternatively, some monkey might have used an Italian thread BB and forced it in the same way. Either way, I detect bodging.

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